Abstract: Apparatus and methods are disclosed for an ion source that comprises a flow-through ultraviolet lamp for photoionization. One embodiment of the apparatus comprises a tubular outer element and a tubular inner element. The inner element is disposed within the outer element to provide a space between the inner and outer elements. The inner element is open at its ends to provide a pathway through that element. A gas discharge between the elements produces ultraviolet radiation, which transmits through the wall of the inner element into the region within the inner element and ionizes molecules that flow through the region. The ion source can be employed in conjunction with a mass analyzer for mass spectrometry. In the method for ionizing molecules in an ion source, vaporized molecules are flowed through the region within the inner element, the region being surrounded by UV radiation. The radiation ionizes vaporized molecules in the surrounded region.

Abstract: For generation and delivery of ions from an ionization chamber through an ion entrance orifice to a mass analyzer operating at high vacuum, high pass ion filtration is effected within the ionization chamber by application of electrical potentials to an electrode associated with the ion entrance orifice and to an electrode between the ionization region and the ion entrance orifice to create a retarding electric field upstream from the ion entrance orifice. The retarding electric field hinders the movement to the ion entrance orifice of ions having drift velocities below a lower limit, and as the retarding voltage gradient is made steeper, the lower limit increases.

Abstract: For delivery of ions from a higher pressure ion source to a mass analyzer operating at high vacuum, high pass ion filtration is effected within a dielectric capillary interface between the higher pressure ionization chamber and the lower pressure environment of a mass analyzer, by application of electrical potentials to end electrodes and to at least one electrode associated with the dielectric capillary between the ends, to create an end-to-end electric field generally opposing gas flow-assisted movement of ions from the upstream end to the downstream end, and to create a steeper voltage gradient along an upstream portion than along a downstream portion of the capillary. The voltage gradient along the steeper upstream portion of the capillary is sufficiently steep to cause ions having drift velocities below a lower limit to stall within the capillary. The respective potentials may be adjusted to increase the steepness of the upstream voltage gradient to increase the drift velocity lower limit.

Abstract: The present invention provides novel systems for sequencing nucleic acid molecules using dNTPs that are 3′ end labeled with cleavable tags that block further extension and uniquely identify the bases to which they are attached. Removal of the tags liberates the 3′ ends of the extension products for further extension. In related embodiments, oligonucleotides containing sequence-related cleavable tags are employed in a ligation reaction to determine the sequence of a particular DNA sample.

Abstract: An atmospheric pressure ion source, e.g. for a mass spectrometer, that produces ions by atmospheric pressure photoionization (APPI). It includes a vaporizer, a photon source for photoionizing vapor molecules upon exit from the vaporizer, a passageway for transporting ions to, for example, a mass spectrometer system, and a means for directing the ions into the passageway. The center axis of the vaporizer and the center axis of the passageway form an angle that may be about 90 degrees. Included in the invention is a method for creating ions by atmospheric pressure photoionization along an axis and directing them into a passageway oriented at an angle to that axis.

Abstract: For delivery of ions from a higher pressure ion source to a mass analyzer operating at high vacuum, high pass ion filtration is effected within a dielectric capillary interface between the higher pressure ionization chamber and the lower pressure environment of a mass analyzer, by application of electrical potentials to end electrodes and to at least one electrode associated with the dielectric capillary between the ends, to create an end-to-end electric field generally opposing gas flow-assisted movement of ions from the upstream end to the downstream end, and to create a steeper voltage gradient along an upstream portion than along a downstream portion of the capillary. The voltage gradient along the steeper upstream portion of the capillary is sufficiently steep to cause ions having drift velocities below a lower limit to stall within the capillary. The respective potentials may be adjusted to increase the steepness of the upstream voltage gradient to increase the drift velocity lower limit.

Abstract: A fraction collection system for liquid chromatography includes a conduit, which directs a sample eluent from an LC column through a flow splitter to a destructive analytical detector such as a mass spectrometer to analyze sample components, and to a fraction collector. A nondestructive detector such as a photodetector is positioned near the fraction collector to detect arrival of sample components. Optionally, a nondestructive detector such as a photodetector is situated upstream from the splitter, to detect passing sample components. Time intervals between detection of a calibrant or a sample component at any two of the detectors provide for automatable identification of selected sample components at the sample collector.

Abstract: A ring pole ion guide apparatus and method provide the focusing and confinement advantages of conventional multipoles and the axial field of a conventional DC ring guide all in one device. The ring pole apparatus comprises a ring stack portion and a multipole portion, wherein the ring stack portion essentially overlaps the multipole portion inside and outside along a central axis. The ring pole apparatus can be used in a mass spectrometer system to guide ions from the ion source to the mass spectrometer or between mass spectrometer stages, or to dissociate ions into daughter ions in an ion dissociation system. A single ring pole ion guide can span a plurality of pressure transition stages with several of the rings acting as pressure partitions.

Abstract: A fraction collection system for liquid chromatography includes a conduit, which directs a sample eluent from an LC column through a flow splitter to a destructive analytical detector such as a mass spectrometer to analyze sample components, and to a fraction collector. A nondestructive detector such as a photodetector is positioned near the fraction collector to detect arrival of sample components. Optionally, a nondestructive detector such as a photodetector is situated upstream from the splitter, to detect passing sample components. Time intervals between detection of a calibrant or a sample component at any two of the detectors provide for automatable identification of selected sample components at the sample collector.

Abstract: A conduit for conducting ions from a high pressure ion source to a mass analyzer in mass spectrometry apparatus includes a capillary tube in which the lumenal surface of the bore near at least one end is a surface of an electrically conductive material. In one embodiment the conduit is constructed of a dielectric material and has an electrically conductive coating on an end portion of the lumenal surface.

Abstract: A mass spectrometer method and apparatus improve resolution and sensitivity. A voltage supply is coupled to a mass filter for applying a radio frequency voltage and for operating at at least one selected frequency. An ion optical element such as an entrance lens is driven by a voltage supply that is phase coherent with the voltage applied to the mass filter. The ion beam is tailored so that the phase space relationship of the ions is more closely matched to the acceptance of the mass filter. The ions in the incoming beam are dynamically matched to the acceptance of the mass filter over each cycle of the voltage applied to the mass filter. The ion optical element may be a single entrance lens to which is applied only a single phase coherent voltage.

Abstract: A fraction collection system for liquid chromatography includes a conduit, which directs a sample eluent from an LC column through a flow splitter to a destructive analytical detector such as a mass spectrometer to analyze sample components, and to a fraction collector. A nondestructive detector such as a photodetector is positioned near the fraction collector to detect arrival of sample components. Optionally, a nondestructive detector such as a photodetector is situated upstream from the splitter, to detect passing sample components. Time intervals between detection of a calibrant or a sample component at any two of the detectors provide for automatable identification of selected sample components at the sample collector.

Abstract: Method for identifying low charge, low weight ions with multiple charge states in mass spectrographic analysis. Ions are matched to a charge series by testing peak width, isotope spacing, and isotope ratios, using instrument resolution and information derived from the instrument spectrum. By following these tests erroneous assignment of ions to a series are avoided, providing higher quality data to the user.

Abstract: The invention relates to an apparatus for forming liquid droplets, such as a micro nebulizer, useful for preparing samples for subsequent analysis via MS, AA, ICP, CE/MS, and similar analytical systems. The apparatus has a mechanically stabilized inner microtube or needle, thereby ensuring controllably uniform droplet size. The mechanical stabilization is provided by securing the inner microtube or needle, such as by narrowing the inner diameter of the outer microtube or otherwise narrowing the annular intermediate space between the inner and outer microtubes for a predetermined length. Thus, the inner microtube is secured in a centered or otherwise predetermined fixed radial position, with minimum perturbation of the fluid flow. Further, a tip, when coupled with the exit end of the outer microtube, provides a region in which the sheath fluid flow in the outer microtube stabilizes prior to both exiting the tip and colliding with the liquid analyte exiting the inner microtube.

Abstract: A mass spectrometer is disclosed which yields fast, full-scan spectra over a wide mass-to-charge ratio range. The instrument contains an ion source which generates nearly monoenergetically-pulsed ion packets which spatially focus at a predetermined distance along the drift path of the ions, a mass filter/analyzer which linearly disperses or deflects the ions in the ion-packets by mass-to-charge ratio by applying a traverse, quadratically time-varying and increasing electric field over the entire length of the deflection region of the mass filter/analyzer, and a spatial mass detector. A method of analyzing the mass-to-charge ratio of ions is also disclosed.

Abstract: The invention relates to an apparatus for forming liquid droplets, such as a micro nebulizer, useful for preparing samples for subsequent analysis via MS, AA, ICP, CE/MS, and similar analytical systems. The apparatus has a mechanically stabilized inner microtube or needle, thereby ensuring controllably uniform droplet size The mechanical stabilization is provided by securing the inner microtube or needle, such as by narrowing the inner diameter of the outer microtube or otherwise narrowing the annular intermediate space between the inner and outer microtubes for a predetermined length. Thus, the inner microtube is secured in a centered or otherwise predetermined fixed radial position, with minimum perturbation of the fluid flow. Further, a tip, when coupled with the exit end of the outer microtube, provides a region in which the sheath fluid flow in the outer microtube stabilizes prior to both exiting the tip and colliding with the liquid analyte exiting the inner microtube.

Abstract: The invention relates to an ionization chamber. More particularly, the invention relates to a mass spectrometer system having an electrospray ionization chamber incorporating an asymmetric electrode.

Abstract: A method and apparatus for improving pneumatic nebulization of liquids is taught providing for controllable production of droplet size range generated. The improvement is aimed at nebulizers comprised of concentric tubes, the inner transporting analyte liquid, the outer--inert gas. The improvement comprises altering the outer lip of the free end of the inner tube so as to allow laminar flow of the exiting gas. By alteration of the tip, droplets in a controlled size range can be routinely produced with a minimum of operator adjusting.

Abstract: An automated calibrant system is provided for use in a liquid separation/mass spectrometry (LS/MS) apparatus. The calibrant system is pneumatically pressurized to forcibly move a reference liquid from the calibrant system to an ion source. The ion source is in fluid communication with a switching valve and with a mass spectrometer. The switching valve communicates effluent from a liquid separation system to the source when the switching valve is in a first position, and communicates one or more reference liquids from the calibrant system to the source when the switching valve is in a second position. The switching valve, and liquid handling valves in the calibrant system, can be individually activated manually or by automated means to alternate between analytical and calibration modes of operation in the LS/MS apparatus. A method is also provided for calibrating a mass spectrometer in a LS/MS apparatus during processing of a liquid sample by the liquid separation system.

Abstract: An improved method and apparatus for creating ions through shearing forces of high velocity liquid and gas streams without application of an external electrical field. Ions are susceptible to customary of analysis such as mass spectrometry.